Prosthesis revision systems and methods

ABSTRACT

A system and method for allowing any surgeon, including those surgeons who perform a fewer number of a revision procedure as compared to a more experienced surgeon who performs a greater number of procedures, to provide an improved likelihood of a favorable outcome approaching, if not exceeding, a likelihood of a favorable outcome as performed by a very experienced surgeon with the revision procedure.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/923,203 filed 26 Mar. 2015 which is a continuation-in-partof U.S. patent application Ser. No. 14/584,656, filed 29 Dec. 2014 thatin turn claims benefit of both U.S. Patent Application No. 61/921,528and U.S. Patent Application No. 61/980,188, the contents of theseapplications in their entireties are hereby expressly incorporated byreference thereto for all purposes.

FIELD OF THE INVENTION

The present invention relates generally to orthopedic surgical systemsand procedures employing a prosthetic implant for, and morespecifically, but not exclusively, to joint replacement therapies suchas total hip replacement including controlled installation, positioning,and revisioning of the prosthesis such as during removal and replacementof a prosthetic implant.

BACKGROUND OF THE INVENTION

The subject matter discussed in the background section should not beassumed to be prior art merely as a result of its mention in thebackground section. Similarly, a problem mentioned in the backgroundsection or associated with the subject matter of the background sectionshould not be assumed to have been previously recognized in the priorart. The subject matter in the background section merely representsdifferent approaches, which in and of themselves may also be inventions.

Total hip replacement refers to a surgical procedure where a hip jointis replaced using a prosthetic implant. There are several differenttechniques that may be used, but all include a step of inserting anacetabular component into the acetabulum and positioning it correctly inthree dimensions (along an X, Y, and Z axis).

In total hip replacement (THR) procedures there are advantages topatient outcome when the procedure is performed by a surgeonspecializing in these procedures. Patients of surgeons who do notperform as many procedures can have increased risks of complications,particularly of complications arising from incorrect placement andpositioning of the acetabular component.

The incorrect placement and positioning may arise even when the surgeonunderstood and intended the acetabular component to be inserted andpositioned correctly. This is true because in some techniques, the toolsfor actually installing the acetabular component are crude and providean imprecise, unpredictable coarse positioning outcome.

It is known in some techniques to employ automated and/orcomputer-assisted navigation tools, for example, x-ray fluoroscopy orcomputer guidance systems. There are computer assisted surgerytechniques that can help the surgeon in determining the correctorientation and placement of the acetabular component. However, currenttechnology provides that at some point the surgeon is required to employa hammer/mallet to physically strike a pin or alignment rod. The amountof force applied and the location of the application of the force arevariables that have not been controlled by these navigation tools. Thuseven when the acetabular component is properly positioned and oriented,when actually impacting the acetabular component into place the actuallocation and orientation can differ from the intended optimum locationand orientation. In some cases the tools used can be used to determinethat there is, in fact, some difference in the location and/ororientation. However, once again the surgeon must employ an impactingtool (e.g., the hammer/mallet) to strike the pin or alignment rod toattempt an adjustment. However the resulting location and orientation ofthe acetabular component after the adjustment may not be, in fact, thedesired location and/or orientation. The more familiar that the surgeonis with the use and application of these adjustment tools can reduce therisk to a patient from a less preferred location or orientation. In somecircumstances, quite large impacting forces are applied to theprosthesis by the mallet striking the rod; these forces make fine tuningdifficult at best and there is risk of fracturing and/or shattering theacetabulum during these impacting steps.

Surgical procedures relating to prostheses includes various revisionprocedures in addition to an initial installation or assembly. Theserevision procedures include removal of a prosthesis (or disassembly ofan assembled modular prosthesis) which can be improved. One of theprimary steps in hip, knee and shoulder revision surgery is theextraction of the retained components before surgical reconstruction. Inrevision surgery, the removal of components that are well fixed to boneand or cement can be a very difficult, demanding, and time consuming.Typically, significant damage is done to the remaining host bone byapplication of large impact forces with 3 lb to 4 lb mallets orslap-hammers. In general the retained prosthesis is grasped in somefashion (i.e. either through a hook and hole, vise grip, or threadedscrew) this part of the tool is then attached to a C-clamp with animpaction plate or a slide-hammer (slap-hammer) for application of theimpact force (in reverse to installation impact) for extraction of theprosthesis.

What is needed is a system and method for allowing any surgeon,including those surgeons who perform a fewer number of a revisionprocedure as compared to a more experienced surgeon who performs agreater number of procedures, to provide an improved likelihood of afavorable outcome approaching, if not exceeding, a likelihood of afavorable outcome as performed by a very experienced surgeon with therevision procedure.

BRIEF SUMMARY OF THE INVENTION

Disclosed is a system and method for allowing any surgeon, includingthose surgeons who perform a fewer number of a revision procedure ascompared to a more experienced surgeon who performs a greater number ofprocedures, to provide an improved likelihood of a favorable outcomeapproaching, if not exceeding, a likelihood of a favorable outcome asperformed by a very experienced surgeon with the revision procedure.

The following summary of the invention is provided to facilitate anunderstanding of some of technical features related to total hipreplacement, and is not intended to be a full description of the presentinvention. A full appreciation of the various aspects of the inventioncan be gained by taking the entire specification, claims, drawings, andabstract as a whole. The present invention is applicable to othersurgical procedures, including replacement of other joints replaced by aprosthetic implant in addition to replacement of an acetabulum (hipsocket) with an acetabular component (e.g., a cup). Use of pneumatic andelectric motor implementations have both achieved a proof of conceptdevelopment.

The disclosed concepts involve creation of a system/method/tool/gun thatvibrates an attached prosthesis, e.g., an acetabular cup, and/or appliescontrollable extraction forces to an installed/assembled prosthesis. Thegun would be held in a surgeon's hands and deployed. It would use avibratory energy to insert (not impact) and position the cup intodesired alignment (using current intra-operation measurement systems,navigation, fluoroscopy, and the like) or to extract (again withoutimpact) and remove an installed prosthesis or aid in disassembly of anassembled modular prosthesis.

An embodiment of the present invention may include an application ofextraction forces (required for removal of prosthesis) in orthopedicrevision surgery. Use of a tool, such as a BMD vibrational tool, allowssuperior control of extraction force as compared to the use of the large3 to 4 lb. mallets applying impact forces for removing a bondedprosthesis. The application of impact force with the 4 lb. mallet isoften required for removal a well fixed prosthesis, however, at greatcost and damage to the host bone. This makes the subsequent attempt atreconstruction more difficult and the chance of better outcome for thepatient is reduced. The components of the extraction force (e.g.,frequency and magnitude) can be modulated to just the right amount thatis required to remove the prosthesis, avoiding excessive forces whichcan damage the severely compromised bone encountered in revisionsurgery. Some embodiments may give the surgeon a nuance and controlhenceforth not available. In this manner the surgeon is avoided morefinesse and ability to remove the prosthesis quickly and safely.

One problem with conventional revision procedures include use of largeand uncontrolled impact forces in orthopedic surgery and particularly injoint replacement. The incorporated patent and references have addresseda use of insertion (non-impact) forces for insertion of prosthesis andimplants, which suggests that ultimately the use of force in orthopedicswill be standardized and modulated and reduce or eliminate uncontrolledimpact forces. Embodiments of the present invention may includeadaptations and reconfigurations of the installation tools and conceptsfor use of applying controllable extraction forces in orthopedics. Anability to modulate and control extractive forces in orthopedics(required for removal of implants and rods, for example) gives thesurgeon a better and safer way to remove implants and perform revision(arthroplasty) surgery.

In one embodiment, a first gun-like device is used for accurateimpaction of the acetabular component at the desired location andorientation.

In another embodiment, a second gun-like device is used for fine-tuningof the orientation of the acetabular component, such as one installed bythe first gun-like device, by traditional mallet and tamp, or by othermethodology. However the second gun-like device may be usedindependently of the first gun-like device for adjusting an acetabularcomponent installed using an alternate technique. Similarly the secondgun-like device may be used independently of the first gun-like device,particularly when the initial installation is sufficiently close to thedesired location and orientation. These embodiments are not necessarilylimited to fine-tuning as certain embodiments permit completere-orientation. Some implementations allow for removal of an installedprosthesis.

Another embodiment includes a third gun-like device that combines thefunctions of the first gun-like device and the second gun-like device.This embodiment enables the surgeon to accurately locate, insert,orient, and otherwise position the acetabular component with the singletool.

Another embodiment includes a fourth device that installs the acetabularcomponent without use of the mallet and the rod, or use of alternativesto strike the acetabular component for impacting it into the acetabulum.This embodiment imparts a vibratory motion to an installation rodcoupled to the acetabular component that enables low-force, impactlessinstallation and/or positioning.

An embodiment of the present invention includes use, adaptation, and/orreconfiguration of installation tools described herein for use inextracting (without impact) an installed prosthesis.

An embodiment of the present invention includes use, adaptation, and/orreconfiguration of installation tools described herein for use indisassembling (without impact) an assembled modular prosthesis.

A positioning device for an acetabular cup disposed in a bone, theacetabular cup including an outer shell having a sidewall defining aninner cavity and an opening with the sidewall having a periphery aroundthe opening and with the acetabular cup having a desired abduction anglerelative to the bone and a desired anteversion angle relative to thebone, including a controller including a trigger and a selector; asupport having a proximal end and a distal end opposite of the proximalend, the support further having a longitudinal axis extending from theproximal end to the distal end with the proximal end coupled to thecontroller, the support further having an adapter coupled to the distalend with the adapter configured to secure the acetabular cup; and anumber N, the number N, an integer greater than or equal to 2, oflongitudinal actuators coupled to the controller and disposed around thesupport generally parallel to the longitudinal axis, each the actuatorincluding an associated impact head arranged to strike a portion of theperiphery, each impact head providing an impact strike to a differentportion of the periphery when the associated actuator is selected andtriggered; wherein each the impact strike adjusts one of the anglesrelative to the bone.

An installation device for an acetabular cup disposed in a pelvic bone,the acetabular cup including an outer shell having a sidewall definingan inner cavity and an opening with the sidewall having a peripheryaround the opening and with the acetabular cup having a desiredinstallation depth relative to the bone, a desired abduction anglerelative to the bone, and a desired anteversion angle relative to thebone, including a controller including a trigger; a support having aproximal end and a distal end opposite of said proximal end, saidsupport further having a longitudinal axis extending from said proximalend to said distal end with said proximal end coupled to saidcontroller, said support further having an adapter coupled to saiddistal end with said adapter configured to secure the acetabular cup;and an oscillator coupled to said controller and to said support, saidoscillator configured to control an oscillation frequency and anoscillation magnitude of said support with said oscillation frequencyand said oscillation magnitude configured to install the acetabular cupat the installation depth with the desired abduction angle and thedesired anteversion angle without use of an impact force applied to theacetabular cup.

An installation system for a prosthesis configured to be implanted intoa portion of bone at a desired implantation depth, the prosthesisincluding an attachment system, including an oscillation engineincluding a controller coupled to a vibratory machine generating anoriginal series of pulses having a generation pattern, said generationpattern defining a first duty cycle of said original series of pulses;and a pulse transfer assembly having a proximal end coupled to saidoscillation engine and a distal end, spaced from said proximal end,coupled to the prosthesis with said pulse transfer assembly including aconnector system at said proximal end, said connector systemcomplementary to the attachment system and configured to secure andrigidly hold the prosthesis producing a secured prosthesis with saidpulse transfer assembly communicating an installation series of pulses,responsive to said original series of pulses, to said secured prosthesisproducing an applied series of pulses responsive to said installationseries of pulses; wherein said applied series of pulses are configuredto impart a vibratory motion to said secured prosthesis enabling aninstallation of said secured prosthesis into the portion of bone towithin 95% of the desired implantation depth without a manual impact.

A method for installing an acetabular cup into a prepared socket in apelvic bone, the acetabular cup including an outer shell having asidewall defining an inner cavity and an opening with the sidewallhaving a periphery around the opening and with the acetabular cup havinga desired installation depth relative to the bone, a desired abductionangle relative to the bone, and a desired anteversion angle relative tothe bone, including (a) generating an original series of pulses from anoscillation engine; (b) communicating said original series of pulses tothe acetabular cup producing a communicated series of pulses at saidacetabular cup; (c) vibrating, responsive to said communicated series ofpulses, the acetabular cup to produce a vibrating acetabular cup havinga predetermined vibration pattern; and (d) inserting the vibratingacetabular cup into the prepared socket within a first predefinedthreshold of the installation depth with the desired abduction angle andthe desired anteversion angle without use of an impact force applied tothe acetabular cup.

This method may further include (e) orienting the vibrating acetabularcup within the prepared socket within a second predetermined thresholdof the desired abduction angle and within third predetermined thresholdof the desired anteversion angle.

A method for inserting a prosthesis into a prepared location in a boneof a patient at a desired insertion depth wherein non-vibratoryinsertion forces for inserting the prosthesis to the desired insertiondepth are in a first range, the method including (a) vibrating theprosthesis using a tool to produce a vibrating prosthesis having apredetermined vibration pattern; and (b) inserting the vibratingprosthesis into the prepared location to within a first predeterminedthreshold of the desired insertion depth using vibratory insertionforces in a second range, said second range including a set of valuesless than a lowest value of the first range.

An extraction device for a prosthesis disposed in a bone having anexposed portion, including a controller including a trigger; a supporthaving a proximal end and a distal end opposite of the proximal end, thesupport further having a longitudinal axis extending from the proximalend to the distal end with the proximal end coupled to the controller,the support further having an adapter coupled to the distal end with theadapter configured to engage the exposed portion of the prosthesis; andan oscillator coupled to the controller and to the support, theoscillator configured to control a series of vibratory pulses having anoscillation frequency and an oscillation magnitude of the support withthe oscillation frequency and the oscillation magnitude configured toextract the prosthesis responsive to the series of vibratory pulseswithout impact forces.

An extraction system for a prosthesis installed and bonded into aportion of bone, the prosthesis including an exposed portion,comprising: an oscillation engine including a controller coupled to avibratory machine generating an original series of pulses having ageneration pattern, the generation pattern defining a first duty cycleof the original series of pulses; and a pulse transfer assembly having aproximal end coupled to the oscillation engine and a distal end, spacedfrom the proximal end, coupled to the prosthesis with the pulse transferassembly including a connector system at the proximal end, the connectorsystem configured to secure the exposed portion of the prosthesisproducing a secured prosthesis with the pulse transfer assemblycommunicating an extraction series of pulses, responsive to the originalseries of pulses, to the secured prosthesis producing an applied seriesof ultrasonic pulses responsive to the extraction series of pulses;wherein the applied series of ultrasonic pulses are configured to imparta vibratory motion to the secured prosthesis enabling an extraction ofthe secured prosthesis from the portion of bone.

A method for extracting a prosthesis bonded within a portion of bone,the prosthesis having an exposed portion, including: (a) engaging theexposed portion; (b) generating an original series of pulses from anoscillation engine; (c) communicating the original series of pulses tothe prosthesis producing a communicated series of pulses at theprosthesis; (d) vibrating, responsive to the communicated series ofpulses, the prosthesis to produce a vibrating prosthesis having apredetermined vibration pattern; and (e) extracting the vibratingprosthesis from the portion of bone.

A method for extracting an implant bonded within a live bone of apatient, the prosthesis having an exposed portion, wherein non-vibratoryrevision forces for removing the bonded implant from the living bone arein a first range, the method including: (a) engaging the exposedportion; (b) vibrating the implant using a tool to produce a vibratingimplant having a predetermined vibration pattern including anoscillation; and (c) extracting the vibrating implant from the live boneusing vibratory insertion forces in a second range, the second rangeincluding a set of values less than a lowest value of the first range.

An apparatus for extracting a bonded implant from a live bone of apatient, the prosthesis having an exposed portion, wherein non-vibratoryrevision forces for removing the bonded prosthesis from the live boneare in a first range, including: means for vibrating the bonded implantto produce a vibrating bonded implant having a predetermined vibrationpattern including an oscillation; and means for extracting the vibratingbonded implant from the live bone using vibratory extraction forces in asecond range, the second range including a set of values less than alowest value of the first range.

Any of the embodiments described herein may be used alone or togetherwith one another in any combination. Inventions encompassed within thisspecification may also include embodiments that are only partiallymentioned or alluded to or are not mentioned or alluded to at all inthis brief summary or in the abstract. Although various embodiments ofthe invention may have been motivated by various deficiencies with theprior art, which may be discussed or alluded to in one or more places inthe specification, the embodiments of the invention do not necessarilyaddress any of these deficiencies. In other words, different embodimentsof the invention may address different deficiencies that may bediscussed in the specification. Some embodiments may only partiallyaddress some deficiencies or just one deficiency that may be discussedin the specification, and some embodiments may not address any of thesedeficiencies.

Other features, benefits, and advantages of the present invention willbe apparent upon a review of the present disclosure, including thespecification, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, in which like reference numerals refer toidentical or functionally-similar elements throughout the separate viewsand which are incorporated in and form a part of the specification,further illustrate the present invention and, together with the detaileddescription of the invention, serve to explain the principles of thepresent invention.

FIG. 1 illustrates a representative installation gun;

FIG. 2 illustrates a right-hand detail of the installation gun of FIG.1;

FIG. 3 illustrates a left-hand detail of the installation gun of FIG. 1and generally when combined with FIG. 2 produces the illustration ofFIG. 1;

FIG. 4 illustrates a second representative installation system;

FIG. 5 illustrates a disassembly of the second representativeinstallation system of FIG. 4;

FIG. 6 illustrates a first disassembly view of the pulse transferassembly of the installation system of FIG. 4;

FIG. 7 illustrates a second disassembly view of the pulse transferassembly of the installation system of FIG. 4;

FIG. 8 illustrates a third representative installation system;

FIG. 9 illustrates a disassembly view of the third representativeinstallation system of FIG. 8; and

FIG. 10 illustrates a system illustrating use of tool for extraction ofa prosthesis.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention provide a system and method forallowing any surgeon, including those surgeons who perform a fewernumber of a revision procedure as compared to a more experienced surgeonwho performs a greater number of procedures, to provide an improvedlikelihood of a favorable outcome approaching, if not exceeding, alikelihood of a favorable outcome as performed by a very experiencedsurgeon with the revision procedure. The following description ispresented to enable one of ordinary skill in the art to make and use theinvention and is provided in the context of a patent application and itsrequirements.

Various modifications to the preferred embodiment and the genericprinciples and features described herein will be readily apparent tothose skilled in the art. Thus, the present invention is not intended tobe limited to the embodiment shown but is to be accorded the widestscope consistent with the principles and features described herein.

Definitions

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this general inventive conceptbelongs. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand the present disclosure, and will not be interpreted in an idealizedor overly formal sense unless expressly so defined herein.

The following definitions apply to some of the aspects described withrespect to some embodiments of the invention. These definitions maylikewise be expanded upon herein.

As used herein, the term “or” includes “and/or” and the term “and/or”includes any and all combinations of one or more of the associatedlisted items. Expressions such as “at least one of,” when preceding alist of elements, modify the entire list of elements and do not modifythe individual elements of the list.

As used herein, the singular terms “a,” “an,” and “the” include pluralreferents unless the context clearly dictates otherwise. Thus, forexample, reference to an object can include multiple objects unless thecontext clearly dictates otherwise.

Also, as used in the description herein and throughout the claims thatfollow, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise. It will be understood that when an elementis referred to as being “on” another element, it can be directly on theother element or intervening elements may be present therebetween. Incontrast, when an element is referred to as being “directly on” anotherelement, there are no intervening elements present.

As used herein, the term “set” refers to a collection of one or moreobjects. Thus, for example, a set of objects can include a single objector multiple objects. Objects of a set also can be referred to as membersof the set. Objects of a set can be the same or different. In someinstances, objects of a set can share one or more common properties.

As used herein, the term “adjacent” refers to being near or adjoining.Adjacent objects can be spaced apart from one another or can be inactual or direct contact with one another. In some instances, adjacentobjects can be coupled to one another or can be formed integrally withone another.

As used herein, the terms “connect,” “connected,” and “connecting” referto a direct attachment or link. Connected objects have no or nosubstantial intermediary object or set of objects, as the contextindicates.

As used herein, the terms “couple,” “coupled,” and “coupling” refer toan operational connection or linking. Coupled objects can be directlyconnected to one another or can be indirectly connected to one another,such as via an intermediary set of objects.

As used herein, the terms “substantially” and “substantial” refer to aconsiderable degree or extent. When used in conjunction with an event orcircumstance, the terms can refer to instances in which the event orcircumstance occurs precisely as well as instances in which the event orcircumstance occurs to a close approximation, such as accounting fortypical tolerance levels or variability of the embodiments describedherein.

As used herein, the terms “optional” and “optionally” mean that thesubsequently described event or circumstance may or may not occur andthat the description includes instances where the event or circumstanceoccurs and instances in which it does not.

As used herein, the term “bone” means rigid connective tissue thatconstitute part of a vertebral skeleton, including mineralized osseoustissue, particularly in the context of a living patient undergoing aprosthesis implant into a portion of cortical bone. A living patient,and a surgeon for the patient, both have significant interests inreducing attendant risks of conventional implanting techniques includingfracturing/shattering the bone and improper installation and positioningof the prosthesis within the framework of the patient's skeletal systemand operation.

As used herein, the term “size” refers to a characteristic dimension ofan object. Thus, for example, a size of an object that is spherical canrefer to a diameter of the object. In the case of an object that isnon-spherical, a size of the non-spherical object can refer to adiameter of a corresponding spherical object, where the correspondingspherical object exhibits or has a particular set of derivable ormeasurable properties that are substantially the same as those of thenon-spherical object. Thus, for example, a size of a non-sphericalobject can refer to a diameter of a corresponding spherical object thatexhibits light scattering or other properties that are substantially thesame as those of the non-spherical object. Alternatively, or inconjunction, a size of a non-spherical object can refer to an average ofvarious orthogonal dimensions of the object. Thus, for example, a sizeof an object that is a spheroidal can refer to an average of a majoraxis and a minor axis of the object. When referring to a set of objectsas having a particular size, it is contemplated that the objects canhave a distribution of sizes around the particular size. Thus, as usedherein, a size of a set of objects can refer to a typical size of adistribution of sizes, such as an average size, a median size, or a peaksize.

As used herein, mallet or hammer refers to an orthopedic device made ofstainless steel or other dense material having a weight generally acarpenter's hammer and a stonemason's lump hammer.

As used herein, an impact force for impacting an acetabular component(e.g., an acetabular cup prosthesis) includes forces from striking animpact rod multiple times with the orthopedic device that are generallysimilar to the forces that may be used to drive a three inch nail into apiece of lumber using the carpenter's hammer by striking the nailapproximately a half-dozen times to completely seat the nail. Withoutlimiting the preceding definition, a representative value in someinstances includes a force of approximately 10 lbs/square inch.

As used herein, the term “vibration” or “vibratory” refers to amechanical displacement oscillations (repetitive positional variation intime) about an equilibrium point that includes one or more axes ofmotion. The equilibrium point may, in turn, move, such as for impactlessimplantation in which the equilibrium point is deeper into aninstallation site, for example, a desired depth into live bone. Thesevibrations are forced and responsive to a time-varying disturbance froman oscillation engine or the like applied, directly or indirectly, to astructure (e.g., a prosthesis or other implant) to be installed. Thedisturbance can be a periodic input, a steady-state input, a transientinput, and/or a random input. A periodic input may include a harmonic ornon-harmonic disturbance. Oscillation about the equilibrium point may bedifferent, or similar, for each degree of freedom available for thevibratory motion. For example, there may be one oscillation profilelongitudinally and a second oscillation profile laterally (e.g.,perpendicular to the longitudinal axis), the two profiles generallymatching, related, derived, or independent. An amount of displacement ofan oscillation is generally less than a dimension of the implant, andmay be much less, on the order of about a millimeter or less.

As used herein, the term “ultrasonic” refers to a vibration in which atleast one oscillation component operates at a frequency greater thanabout 20 kHz, and more specifically in a range of 20 kHz to 2-3 GHz, andin some instances in a range of about 20 kHz to about 200 kHz

The following description relates to improvements in a wide-range ofprostheses installations into live bones of patients of surgeons. Thefollowing discussion focuses primarily on total hip replacement (THR) inwhich an acetabular cup prosthesis is installed into the pelvis of thepatient. This cup is complementary to a ball and stem (i.e., a femoralprosthesis) installed into an end of a femur engaging the acetabulumundergoing repair.

As noted in the background, the surgeon prepares the surface of thehipbone which includes attachment of the acetabular prosthesis to thepelvis. Conventionally, this attachment includes a manual implantationin which a mallet is used to strike a tamp that contacts some part ofthe acetabular prosthesis. Repeatedly striking the tamp drives theacetabular prosthesis into the acetabulum. Irrespective of whethercurrent tools of computer navigation, fluoroscopy, and robotics (andother intra-operative measuring tools) have been used, it is extremelyunlikely that the acetabular prosthesis will be in the correctorientation once it has been seated to the proper depth by the series ofhammer strikes. After manual implantation in this way, the surgeon thenmay apply a series of adjusting strikes around a perimeter of theacetabular prosthesis to attempt to adjust to the desired orientation.Currently such post-impaction result is accepted as many surgeonsbelieve that post-impaction adjustment creates an unpredictable andunreliable change which does not therefore warrant any attempts forpost-impaction adjustment.

In most cases, any and all surgeons including an inexperienced surgeonmay not be able to achieve the desired orientation of the acetabularprosthesis in the pelvis by conventional solutions due tounpredictability of the orientation changes responsive to theseadjusting strikes. As noted above, it is most common for any surgeon toavoid post-impaction adjustment as most surgeons understand that they donot have a reliable system or method for improving any particularorientation and could easily introduce more/greater error. The computernavigation systems, fluoroscopy, and other measuring tools are able toprovide the surgeon with information about the current orientation ofthe prosthesis (in real time) during an operation and after theprosthesis has been installed and its deviation from the desiredorientation, but the navigation systems (and others) do not protectagainst torsional forces created by the implanting/positioning strikes.The prosthesis will find its own position in the acetabulum based on theaxial and torsional forces created by the blows of the mallet. Eventhose navigation systems used with robotic systems (e.g., MAKO) thatattempt to secure an implant in the desired orientation prior toimpaction are not guaranteed to result in the installation of theimplant at the desired orientation because the actual implanting forcesare applied by a surgeon swinging a mallet to manually strike the tamp.

A Behzadi Medical Device (BMD) is herein described and enabled thateliminates this crude method (i.e., mallet, tamp, and surgeon-appliedmechanical implanting force) of the prosthesis (e.g., the acetabularcup). A surgeon using the BMD is able to insert the prosthesis exactlywhere desired with proper force, finesse, and accuracy. Depending uponimplementation details, the installation includes insertion of theprosthesis into patient bone, within a desired threshold of metrics forinsertion depth and location) and may also include, when appropriateand/or desired, positioning at a desired orientation with the desiredthreshold further including metrics for insertion orientation). The useof the BMD reduces risks of fracturing and/or shattering the bonereceiving the prosthesis and allows for rapid, efficient, and accurate(atraumatic) installation of the prosthesis. The BMD provides a viableinterface for computer navigation assistance (also useable with allintraoperative measuring tools including fluoroscopy) during theinstallation as a lighter more responsive touch may be used.

The BMD encompasses many different embodiments for installation and/orpositioning of a prosthesis and may be adapted for a wide range ofprostheses in addition to installation and/or positioning of anacetabular prosthesis during THR.

FIG. 1 illustrates a representative installation gun 100; FIG. 2illustrates a right-hand detail of the installation gun 100; and FIG. 3illustrates a left-hand detail of installation gun of 100 and generallywhen combined with FIG. 2 produces the illustration of FIG. 1.Installation gun 100 is represented as operable using pneumatics, thoughother implementations may use other mechanisms for creating a desiredvibratory motion of prosthesis to be installed.

Installation gun 100 is used to control precisely one or both of (i)insertion, and (ii) abduction and anteversion angles of a prostheticcomponent. Installation gun 100 preferably allows both installation ofan acetabular cup into an acetabulum at a desired depth and orientationof the cup for both abduction and anteversion to desired values. Thefollowing reference numbers in Table I refer to elements identified inFIG. 1-FIG. 3:

TABLE I Device 100 Elements 102 Middle guide housing 104 Klip 106Kuciste 108 CILINDAR 110 Cjev 112 Poklopac 114 54 mm acetabular cup 116Body 118 Valve 120 Bottom cap 122 Upper guide housing 124 Handle cam 126DIN 3771 6 x 1,8 - N -NBR 70 128 Main Air Inlet - Input Tube 130 Trigger132 Trigger pin 134 DIN 3771 6 x 1,8 - N -NBR 70 136 MirrorAR15 - HandGrip 1 138 Crossover Tube 140 9657K103 compression spring 142 Elongatetube 144 Lower guide housing 146 Primary adapter 148 Housing

Installation gun 100 includes a controller with a handle supporting anelongate tube 142 that terminates in adapter 146 that engages cup 114.Operation of trigger 130 initiates a motion of elongate tube 142. Thismotion is referred to herein as an installation force and/orinstallation motion that is much less than the impact force used in aconventional replacement process. An exterior housing 148 allows theoperator to hold and position prosthesis 114 while elongate tube 142moves within. Some embodiments may include a handle or other grip inaddition to or in lieu of housing 148 that allows the operator to holdand operate installation gun 100 without interfering with the mechanismthat provides a direct transfer of installation motion to prosthesis114. The illustrated embodiment includes prosthesis 114 held securely byadapter 146 allowing a tilting and/or rotation of gun 100 about any axisto be reflected in the position/orientation of the secured prosthesis.

The installation motion includes constant, cyclic, periodic, and/orrandom motion (amplitude and/or frequency) that allows the operator toinstall cup 114 into the desired position (depth and orientation)without application of an impact force. There may be continuous movementor oscillations in one or more of six degrees of freedom includingtranslation(s) and/or rotation(s) of adapter 146 about the X, Y, Z axes(e.g., oscillating translation(s) and/or oscillating/continuousrotation(s) which could be different for different axes such astranslating back and forth in the direction of the longitudinal axis ofthe central support while rotating continuously around the longitudinalaxis). This installation motion may include continuous or intermittentvery high frequency movements and oscillations of small amplitude thatallow the operator to easily install the prosthetic component in thedesired location, and preferably also to allow the operator to also setthe desired angles for abduction and anteversion.

In some implementations, the controller includes a stored programprocessing system that includes a processing unit that executesinstructions retrieved from memory. Those instructions could control theselection of the motion parameters autonomously to achieve desiredvalues for depth, abduction and anteversion entered into by the surgeonor by a computer aided medical computing system such as the computernavigation system. Alternatively those instructions could be used tosupplement manual operation to aid or suggest selection of the motionparameters.

For more automated systems, consistent and unvarying motion parametersare not required and it may be that a varying dynamic adjustment of themotion parameters better conform to an adjustment profile of the cupinstalled into the acetabulum and status of the installation. Anadjustment profile is a characterization of the relative ease by whichdepth, abduction and anteversion angles may be adjusted in positive andnegative directions. In some situations these values may not be the sameand the installation gun could be enhanced to adjust for thesedifferences. For example, a unit of force applied to pure positiveanteversion may adjust anteversion in the positive direction by a firstunit of distance while under the same conditions that unit of forceapplied to pure negative anteversion may adjust anteversion in thenegative direction by a second unit of distance different from the firstunit. And these differences may vary as a function of the magnitude ofthe actual angle(s). For example, as the anteversion increases it may bethat the same unit of force results in a different responsive change inthe actual distance adjusted. The adjustment profile when used helps theoperator when selecting the actuators and the impact force(s) to beapplied. Using a feedback system of the current real-time depth andorientation enables the adjustment profile to dynamically select/modifythe motion parameters appropriately during different phases of theinstallation. One set of motion parameters may be used when primarilysetting the depth of the implant and then another set used when thedesired depth is achieved so that fine tuning of the abduction andanteversion angles is accomplished more efficiently, all without use ofimpact forces in setting the depth and/or angle adjustment(s).

This device better enables computer navigation as theinstallation/adjustment forces are reduced as compared to the impactingmethod. This makes the required forces more compatible with computernavigation systems used in medical procedures which do not have thecapabilities or control systems in place to actually provide impactingforces for seating the prosthetic component. And without that, thecomputer is at best relegated to a role of providing after-the-factassessments of the consequences of the surgeon's manual strikes of theorthopedic mallet. (Also provides information before and during theimpaction. It is a problem that the very act of impaction introducesvariability and error in positioning and alignment of the prosthesis.

FIG. 4 illustrates a second representative installation system 400including a pulse transfer assembly 405 and an oscillation engine 410;FIG. 5 illustrates a disassembly of second representative installationsystem 400; FIG. 6 illustrates a first disassembly view of pulsetransfer assembly 405; and FIG. 7 illustrates a second disassembly viewof pulse transfer assembly 405 of installation system 400.

Installation system 400 is designed for installing a prosthesis that, inturn, is configured to be implanted into a portion of bone at a desiredimplantation depth. The prosthesis includes some type of attachmentsystem (e.g., one or more threaded inserts, mechanical coupler, link, orthe like) allowing the prosthesis to be securely and rigidly held by anobject such that a translation and/or a rotation of the object about anyaxis results in a direct corresponding translation and/or rotation ofthe secured prosthesis.

Oscillation engine 410 includes a controller coupled to a vibratorymachine that generates an original series of pulses having a generationpattern. This generation pattern defines a first duty cycle of theoriginal series of pulses including one or more of a first pulseamplitude, a first pulse direction, a first pulse duration, and a firstpulse time window. This is not to suggest that the amplitude, direction,duration, or pulse time window for each pulse of the original pulseseries are uniform with respect to each other. Pulse direction mayinclude motion having any of six degrees of freedom—translation alongone or more of any axis of three orthogonal axes and/or rotation aboutone or more of these three axes. Oscillation engine 410 includes anelectric motor powered by energy from a battery, though other motors andenergy sources may be used.

Pulse transfer assembly 405 includes a proximal end 415 coupled tooscillation engine 410 and a distal end 420, spaced from proximal end420, coupled to the prosthesis using a connector system 425. Pulsetransfer assembly 405 receives the original series of pulses fromoscillation engine 410 and produces, responsive to the original seriesof pulses, an installation series of pulses having an installationpattern. Similar to the generation pattern, the installation patterndefines a second duty cycle of the installation series of pulsesincluding a second pulse amplitude, a second pulse direction, a secondpulse duration, and a second pulse time window. Again, this is not tosuggest that the amplitude, direction, duration, or pulse time windowfor each pulse of the installation pulse series are uniform with respectto each other. Pulse direction may include motion having any of sixdegrees of freedom—translation along one or more of any axis of threeorthogonal axes and/or rotation about one or more of these three axes.

For some embodiments of pulse transfer assembly 405, the installationseries of pulses will be strongly linked to the original series andthere will be a close match, if not identical match, between the twoseries. Some embodiments may include a more complex pulse transferassembly 405 that produces an installation series that is moredifferent, or very different, from the original series.

Connector system 425 (e.g., one or more threaded studs complementary tothe threaded inserts of the prosthesis, or other complementarymechanical coupling system) is disposed at proximal end 420. Connectorsystem 425 is configured to secure and rigidly hold the prosthesis. Inthis way, the attached prosthesis becomes a secured prosthesis whenengaged with connector system 425.

Pulse transfer assembly 405 communicates the installation series ofpulses to the secured prosthesis and produces an applied series ofpulses that are responsive to the installation series of pulses. Similarto the generation pattern and the installation pattern, the appliedpattern defines a third duty cycle of the applied series of pulsesincluding a third pulse amplitude, a third pulse direction, a thirdpulse duration, and a third pulse time window. Again, this is not tosuggest that the amplitude, direction, duration, or pulse time windowfor each pulse of the applied pulse series are uniform with respect toeach other. Pulse direction may include motion having any of six degreesof freedom—translation along one or more of any axis of three orthogonalaxes and/or rotation about one or more of these three axes.

For some embodiments of pulse transfer assembly 405, the applied seriesof pulses will be strongly linked to the original series and/or theinstallation series and there will be a close, if not identical, matchbetween the series. Some embodiments may include a more complex pulsetransfer assembly 405 that produces an applied series that is moredifferent, or very different, from the original series and/or theinstallation series. In some embodiments, for example one or morecomponents may be integrated together (for example, integratingoscillation engine 410 with pulse transfer assembly 405) so that thefirst series and the second series, if they exist independently arenearly identical if not identical).

The applied series of pulses are designed to impart a vibratory motionto the secured prosthesis that enable an installation of the securedprosthesis into the portion of bone to within 95% of the desiredimplantation depth without a manual impact. That is, in operation, theoriginal pulses from oscillation engine 410 propagate through pulsetransfer assembly 405 (with implementation-depending varying levels offidelity) to produce the vibratory motion to the prosthesis secured toconnector system 425. In a first implementation, the vibratory motionallows implanting without manual impacts on the prosthesis and in asecond mode an orientation of the implanted secured prosthesis may beadjusted by rotations of installation system 400 while the vibratorymotion is active, also without manual impact. In some implementations,the pulse generation may produce different vibratory motions optimizedfor these different modes.

Installation system 400 includes an optional sensor 430 (e.g., a flexsensor or the like) to provide a measurement (e.g., quantitative and/orqualitative) of the installation pulse pattern communicated by pulsetransfer assembly 405. This measurement may be used as part of a manualor computerized feedback system to aid in installation of a prosthesis.For example, in some implementations, the desired applied pulse patternof the applied series of pulses (e.g., the vibrational motion of theprosthesis) may be a function of a particular installation pulsepattern, which can be measured and set through sensor 430. In additionto, or alternatively, other sensors may aid the surgeon or an automatedinstallation system operating installation system 400, such as a bonedensity sensor or other mechanism to characterize the bone receiving theprosthesis to establish a desired applied pulse pattern for optimalinstallation.

The disassembled views of FIG. 6 and FIG. 7 detail a particularimplementation of pulse transfer assembly 405, it being understood thatthere are many possible ways of creating and communicating an appliedpulse pattern responsive to a series of generation pulses from anoscillation engine. The illustrated structure of FIG. 6 and FIG. 7generate primarily longitudinal/axial pulses in response to primarilylongitudinal/axial generation pulses from oscillation engine 410.

Pulse transfer assembly 405 includes an outer housing 435 containing anupper transfer assembly 640, a lower transfer assembly 645 and a centralassembly 650. Central assembly 650 includes a double anvil 655 thatcouples upper transfer assembly 640 to lower transfer assembly 645.Outer housing 635 and central assembly 650 each include a port allowingsensor 630 to be inserted into central assembly 650 between an end ofdouble anvil 655 and one of the upper/lower transfer assemblies.

Upper transfer assembly 640 and lower transfer assembly 645 each includea support 660 coupled to outer housing 435 by a pair of connectors. Atransfer rod 665 is moveably disposed through an axial aperture in eachsupport 660, with each transfer rod 665 including a head at one endconfigured to strike an end of double anvil 655 and a coupling structureat a second end. A compression spring 670 is disposed on each transferrod 665 between support 660 and the head. The coupling structure ofupper transfer assembly 640 cooperates with oscillation engine 410 toreceive the generated pulse series. The coupling structure of lowertransfer assembly 645 includes connector system 425 for securing theprosthesis. Some embodiments may include an adapter, not shown, thatadapts connector system 425 to a particular prosthesis, differentadapters allowing use of pulse transfer assembly 405 with differentprosthesis.

Central assembly 650 includes a support 675 coupled to outer housing 435by a connector and receives double anvil 655 which moves freely withinsupport 675. The heads of the upper transfer assembly and the lowertransfer assembly are disposed within support 675 and arranged to strikecorresponding ends of double anvil 655 during pulse generation.

In operation, oscillation engine 410 generates pulses that aretransferred via pulse transfer assembly 405 to the prosthesis secured byconnector system 425. The pulse transfer assembly 405, via uppertransfer assembly 640, receives the generated pulses using transfer rod665. Transfer rod 665 of upper transfer assembly 640 moves withinsupport 660 of upper transfer assembly 640 to communicate pulses todouble anvil 655 moving within support 675. Double anvil 655, in turn,communicates pulses to transfer rod 665 of lower transfer assembly 645to produce vibratory motion of a prosthesis secured to connector system425. Transfer rods 665 move, in this illustrated embodiment, primarilylongitudinally/axially within outer housing 435 (a longitudinal axisdefined as extending between proximate end 415 and distal end 420. Inthis way, the surgeon may use outer housing 435 as a hand hold wheninstalling and/or positioning the vibrating prosthesis.

The use of discrete transfer portions (e.g., upper, central, and lowertransfer assemblies) for pulse transfer assembly 405 allows a form ofloose coupling between oscillation engine 410 and a secured prosthesis.In this way pulses from oscillation engine 410 are converted into avibratory motion of the prosthesis as it is urged into the bone duringoperation. Some embodiments may provide a stronger coupling by directlysecuring one component to another, or substituting a single componentfor a pair of components.

FIG. 8 illustrates a third representative installation system 800; andFIG. 9 illustrates a disassembly view of third representativeinstallation system 800.

The embodiments of FIG. 4-FIG. 8 have demonstrated insertion of aprosthetic cup into a bone substitute substrate with ease and a greatlyreduced force as compared to use of a mallet and tamp, especially as noimpaction was required. While the insertion was taking place andvibrational motion was present at the prosthesis, the prosthesis couldbe positioned with relative ease by torquing on a handle/outer housingto an exact desired alignment/position. The insertion force is variableand ranges between 20 to 800 pounds of force. Importantly the potentialfor use of significantly smaller forces in application of the prosthesis(in this case the acetabular prosthesis) in bone substrate with thepresent invention is demonstrated to be achievable.

Similarly to installation system 100 and installation system 400,installation system 800 is used to control precisely one or both of (i)installation and (ii) abduction and anteversion angles of a prostheticcomponent. Installation system 800 preferably allows both installationof an acetabular cup into an acetabulum at a desired depth andorientation of the cup for both abduction and anteversion to desiredvalues. The following reference numbers in Table II refer to elementsidentified in FIG. 8-FIG. 9:

TABLE II Device 800 Elements 802 Air Inlet 804 Trigger 806 Needle Valve808 Valve Body 810 Throttle Cap 812 Piston 814 Cylinder 816 Driver 818Needle Block 820 Needles 822 Suspension Springs 824 Anvil 826 Nozzle 828Connector Rod 830 Prosthesis (e.g., acetabular cup)

Installation system 800 includes a controller with a handle supportingan elongate rod that terminates in a connector system that engagesprosthesis 830. Operation of trigger 804 initiates a motion of theelongate rod. This motion is referred to herein as an installation forceand/or installation motion that is much less than the impact force usedin a conventional replacement process. An exterior housing allows theoperator to hold and position prosthesis 830 while the elongate rodmoves within. Some embodiments may include a handle or other grip inaddition to or in lieu of the housing that allows the surgeon operatorto hold and operate installation system 800 without interfering with themechanism that provides a direct transfer of installation motion. Theillustrated embodiment includes prosthesis 830 held securely allowing atilting and/or rotation of installation system about any axis to bereflected in the position/orientation of the secured prosthesis.

The actuator is pneumatically operated oscillation device that providesthe impact and vibration action this device uses to set the socket (itbeing understand that alternative motive systems may be used in additionto, or alternatively to, a pneumatic system). Alternatives includingmechanical and/or electromechanical systems, motors, and/or engines. Theactuator includes air inlet port 802, trigger 804, needle valve 806,cylinder 814, and piston 812.

Air is introduced through inlet port 802 and as trigger 804 is squeezedneedle valve 806 admits air into the cylinder 814 pushing piston 812 toan opposing end of cylinder 814. At the opposite end piston 812 opens aport allowing the air to be admitted and pushing the piston 812 back tothe original position.

This action provides the motive power for operation of the device andfunctions in this embodiment at up to 70 Hz. The frequency can beadjusted by trigger 804 and an available air pressure at air inlet port802.

As piston 812 impacts driver 816, driver 816 impacts needles 820 ofneedle block 818. Needles 820 strike anvil 824 which is directlyconnected to prosthesis 830 via connecting rod 828.

Suspension springs 822 provide a flexibility to apply more or less totalforce. This flexibility allows force to be applied equally aroundprosthesis 830 or more force to one side of prosthesis 830 in order tolocate prosthesis 830 at an optimum/desired orientation. Installationsystem 800 illustrates a BMD having a more strongly coupled pulsetransfer system between an oscillation engine and prosthesis 830.

The nature and type of coupling of pulse communications between theoscillation engine and the prosthesis may be varied in several differentways. For example, in some implementations, needles 820 of needle block818 are independently moveable and respond differently to piston 812motion. In other implementations, the needles may be fused together orotherwise integrated together, while in other implementations needles820 and needle block 818 may be replaced by an alternative cylinderstructure.

As illustrated, while installation embodiments provide for a primarilylongitudinal implementation, installation system 800 includes a designfeature intended to allow the inserting/vibratory force to be “steered”by applying forces to be concentrated on one side or another of theprosthesis. Implementations that produce a randomized vibrationalmotion, including “lateral” motion components in addition to, or in lieuof, the primarily longitudinal vibrational motion of the disclosedembodiments may be helpful for installation of prosthesis in a widerange of applications including THR surgery.

Installation system 400 and installation system 800 included anoscillation engine producing pulses at approximately 60 Hz. System 400operated at 60 Hz while system 800 was capable of operating at 48 to 68Hz. In testing, approximately 4 seconds of operation resulted in adesired insertion and alignment of the prosthesis (meaning about 240cycles of the oscillation engine). Conventional surgery using a malletstriking a tamp to impact the cup into place is generally complete after10 blows of the mallet/hammer.

FIG. 10 illustrates a system 1000 illustrating use of a tool 1005 forextraction of a prosthesis 1010 bonded within a portion of live bone1015. Bonded prosthesis 1010 includes an exposed portion 1020. Tool 1005may include a version of a BMD tool as described herein or othernon-impacting tool capable of producing extractiveforces/pulses/vibrations (which may include mechanical ultrasonicpatterns).

Tool 1005 cooperates with, or is integrated into, a mechanical assembly1025 that includes an adaptor portion 1030 to mechanically engageexposed portion 1020. There are many ways to implement mechanicalassembly 1025 to communicate extraction forces/pulses from tool 1005 tobonded prosthesis 1010 through the mechanical coupling to exposedportion 1020.

System 1000 includes one particular implementation for mechanicalassembly 1025 to facilitate one description of an embodiment of thepresent invention. Mechanical assembly 1025 includes a C-portion 1035coupled to adaptor portion 1030, the C-portion including a pair oflateral legs coupled to opposite ends of a longitudinal leg generallyparallel to an extraction path intended for bonded prosthesis 1010during extraction. One of the lateral legs includes an adaptor portion1040 for engaging tool 1005 allowing tool 1005 to transfer extractionforce(s)/pulses to bonded prosthesis 1010.

In some embodiments, the mechanical coupling of adaptor portion 1030 toexposed portion 1020 is such that vibratory pulses/excitement producedby tool 1005 and communicated by mechanical assembly 1025 are able to becommunicated to bonded prosthesis 1010 to produce avibrating/oscillating bonded prosthesis 1010 as an aid in extraction,sometimes the vibration is applied while concurrently applying a forcewithdrawing prosthesis from the portion of bone. This is in contrast toany system which simply applied a vibratory to a bonded structure with agoal of breaking up a cured bonding agent securing the structure inplace.

Mechanical assembly 1025 may include an optional handle 1045 to aid thesurgeon/operator when extracting bonded prosthesis 1010 from boneportion 1015 in response to extractive impulses provided by tool 1005.

Experimental

Both system 400 and system 800 were tested in a bone substitutesubstrate with a standard Zimmer acetabular cup using standard techniqueof under reaming a prepared surface by 1 mm and inserting a cup that wasone millimeter larger. The substrate was chosen as the best optionavailable to us to study this concept, namely a dense foam material. Itwas recognized that certain properties of bone would not be representedhere (e.g. an ability of the substrate to stretch before failure).

Both versions demonstrated easy insertion and positioning of theprosthetic cup within the chosen substrate. We were able to move the cupin the substrate with relative ease. There was no requirement for amallet or hammer for application of a large impact. These experimentsdemonstrated that the prosthetic cups could be inserted in bonesubstitute substrates with significantly less force and more controlthan what could be done with blows of a hammer or mallet. We surmisethat the same phenomena can be reproduced in human bone. We envision theprosthetic cup being inserted with ease with very little force.

Additionally we believe that simultaneously, while the cup is beinginserted, the position of the cup can be adjusted under directvisualization with any intra-operative measurement system (navigation,fluoroscopy, etc.). This invention provides a system that allowsinsertion of a prosthetic component with NON-traumatic force (insertion)as opposed to traumatic force (impaction).

Experimental Configuration—System 400

Oscillation engine 410 included a Craftsman G2 Hammerhead nailer used todrive fairly large framing nails into wood in confined spaces byapplying a series of small impacts very rapidly in contrast toapplication of few large impacts.

The bone substitute was 15 pound density urethane foam to represent thepelvic acetabulum. It was shaped with a standard cutting tool commonlyused to clean up a patient's damaged acetabulum. A 54 mm cup and a 53 mmcutter were used in testing.

In one test, the cup was inserted using a mallet and tamp, withimpaction complete after 7 strikes. Re-orientation of the cup wasrequired by further strikes on a periphery of the cup after impaction toachieve a desired orientation. It was qualitatively determined that thefeel and insertion were consistent with impaction into bone.

An embodiment of system 400 was used in lieu of the mallet and tampmethod. Several insertions were performed, with the insertions found tobe much more gradual; allowing the cup to be guided into position (depthand orientation during insertion). Final corrective positioning iseasily achievable using lateral hand pressure to rotate the cup withinthe substrate while power was applied to the oscillation engine.

Further testing using the sensor included general static load detectiondone to determine the static (non-impact) load to push the cup into theprepared socket model. This provided a baseline for comparison to theimpact load testing. The prosthesis was provided above a prepared socketwith a screw mounted to the cup to transmit a force applied from a benchvise. The handle of the vice was turned to apply an even force tocompress the cup into the socket until the cup was fully seated. The cupbegan to move into the socket at about an insertion force of ˜200 poundsand gradually increased as diameter of cup inserted into socketincreased to a maximum of 375 pounds which remained constant until thecup was fully seated.

Installation system 400 was next used to install the cup into asimilarly prepared socket. Five tests were done, using different framerates and setup procedures, to determine how to get the most meaningfulresults. All tests used a 54 mm acetabular Cup. The oscillation engineran at an indicated 60 impacts/second. The first two tests were done at2,000 frames/second, which wasn't fast enough to capture all the impactevents, but helped with designing the proper setup. Test 3 used theoscillation engine in an already used socket, 4,000 frames per second.Test 4 used the oscillation engine in an unused foam socket at 53 mm,4,000 frames per second.

Test 3: In already compacted socket, the cup was pulsed using theoscillation engine and the pulse transfer assembly. Recorded strikesbetween 500 and 800 lbs, with an average recorded pulse duration 0.8 ms.

Test 4: Into an unused 53 mm socket, the cup was pulsed using theoscillation engine and the pulse transfer assembly. Recorded impactsbetween 250 and 800 lbs, and an average recorded pulse duration 0.8 ms.Insertion completed in 3.37 seconds, 202 impact hits.

Test 5: Into an unused 53 mm socket, the cup was inserted with standardhammer (for reference). Recorded impacts between 500 and 800 lbs, and anaverage recorded pulse duration 22.0 ms. Insertion completed in 4seconds using 10 impact hits for a total pressure time of 220 ms. Thistest was performed rapidly to complete it in 5 seconds for goodcomparability with tests 3 and 4 used 240 hits in 4 seconds, with asingle hit duration of 0.8 ms, for a total pressure time of 192 ms.

In non-rigorous comparison testing without a direct comparison betweensystem 400 and system 800, generally it appears that the forces used forinstallation using system 800 were lower than system 400 by a factor of10. This suggests that there are certain optimizing characteristics foroperation of an installation system. There are questions such as to howlow these forces can be modulated and still allow easy insertion of theprosthetic cup in this model and in bone. What is the lowest forcerequired for insertion of a prosthetic cup in to this substrate usingthe disclosed concepts? What is the lowest force required for insertionof a prosthetic cup into hard bone using these concepts? And what is thelowest force required for insertion of a prosthetic cup into soft andosteoporotic bone using these concepts? These are the questions that canbe addressed in future phase of implementations of the presentinvention.

Additionally, basic studies can further be conducted to correlate adensity and a porosity of bone at various ages (e.g., through a cadaverstudy) with an appropriate force range and vibratory motion patternrequired to insert a cup using the present invention. For example asurgeon will be able to insert sensing equipment in patient bone, or useother evaluative procedures, (preoperative planning or while performingthe procedure for example) to assess porosity and density of bone. Onceknown, the density or other bone characteristic is used to set anappropriate vibratory pattern including a force range on an installationsystem, and thus use a minimal required force to insert and/or positionthe prosthesis.

BMD is a “must have” device for all medical device companies andsurgeons. Without BMD the Implantation problem is not addressed,regardless of the recent advances in technologies in hip replacementsurgery (i.e.; Navigation, Fluoroscopy, MAKO/robotics,accelerometers/gyro meters, etc.). Acetabular component (cup)positioning remains the biggest problem in hip replacement surgery.Implantation is the final step where error is introduced into the systemand heretofore no attention has been brought to this problem. Currenttechnologies have brought significant awareness to the position of theimplants within the pelvis during surgery, prior to impaction. However,these techniques do not assist in the final step of implantation.

BMD allows all real time information technologies to utilize (a tool) toprecisely and accurately implant the acetabular component (cup) withinthe pelvic acetabulum. BMD device coupled with use of navigationtechnology and fluoroscopy and (other novel measuring devices) is theonly device that will allow surgeons from all walks of life, (lowvolume/high volume) to perform a perfect hip replacement with respect toacetabular component (cup) placement. With the use of BMD, surgeons canfeel confident that they are doing a good job with acetabular componentpositioning, achieving the “perfect cup” every time. Hence the BMDconcept eliminates the most common cause of complications in hipreplacement surgery which has forever plagued the surgeon, the patientsand the society in general.

It is known to use ultra sound devices in connection with some aspectsof THR, primarily for implant removal (as some components may beinstalled using a cement that may be softened using ultrasound energy).There may be some suggestion that some ultrasonic devices that employ“ultrasound” energy could be used to insert a prosthesis for final fit,but it is in the context of a femoral component and it is believed thatthese devices are not presently actually used in the process). Someembodiments of BMD, in contrast, can simply be a vibratory device (nonultrasonic), and may not be ultrasonic and some implementations mayinclude ultrasonic operation, and may be more profound than simply animplantation device as it is most preferably a positioning device forthe acetabular component in THR. Further, there is a discussion thatultrasound devices may be used to prepare bones for implanting aprosthesis. BMD does not address preparation of the bone as this is nota primary thrust of this aspect of the present invention. Someimplementations of BMD may include a similar or related feature. Theforces applied by the vibration will be less than an impact force andpreferably enable installation without requiring impact forces appliedto the mechanism by which the equilibrium point is moved duringinstallation of the vibrating implant. That mechanism may be handpressure from the surgeon guiding the vibrating implant into a desireddepth and orientation or may include some other mechanical applicationof less-than-impact force to adjust the equilibrium point. An extractingversion that supplies/applies non-impactful extractive forces may beused in other contexts in addition to extracting a bonded prosthesisfrom a portion of bone.

Some embodiments BMD include devices that concern themselves with properinstallation and positioning of the prosthesis (e.g., an acetabularcomponent) at the time of implanting of the prosthesis. Veryspecifically, it uses some form of vibratory energy coupled with avariety of “real time measurement systems” to POSITION the cup in aperfect alignment with minimal use of force. A prosthesis, such as forexample, an acetabular cup, resists insertion. Once inserted, the cupresists changes to the inserted orientation. The BMDs of the presentinvention produce an insertion vibratory motion of a secured prosthesisthat reduces the forces resisting insertion. In some implementations,the BMD may produce a positioning vibratory motion that reduces theforces resisting changes to the orientation. There are someimplementations that produce both types of motion, either as a singlevibratory profile or alternative profiles. In the present context forpurposes of the present invention, the vibratory motion is characterizedas “floating” the prosthesis as the prosthesis can become much simplerto insert and/or re-orient while the desired vibratory motion isavailable to the prosthesis. Some embodiments are described as producingvibrating prosthesis with a predetermined vibration pattern. In someimplementations, the predetermined vibration pattern is predictable andlargely completely defined in advance. In other implementations, thepredetermined vibration pattern includes randomized vibratory motion inone or more motion freedoms of the available degrees of freedom (up tosix degrees of freedom). That is, whichever translation or rotationalfreedom of motion is defined for the vibrating prosthesis, any of themmay have an intentional randomness component, varying from large tosmall. In some cases the randomness component in any particular motionmay be large and in some cases predominate the motion. In other casesthe randomness component may be relatively small as to be barelydetectable.

The system and methods above has been described in general terms as anaid to understanding details of preferred embodiments of the presentinvention. In the description herein, numerous specific details areprovided, such as examples of components and/or methods, to provide athorough understanding of embodiments of the present invention. Somefeatures and benefits of the present invention are realized in suchmodes and are not required in every case. One skilled in the relevantart will recognize, however, that an embodiment of the invention can bepracticed without one or more of the specific details, or with otherapparatus, systems, assemblies, methods, components, materials, parts,and/or the like. In other instances, well-known structures, materials,or operations are not specifically shown or described in detail to avoidobscuring aspects of embodiments of the present invention.

Reference throughout this specification to “one embodiment”, “anembodiment”, or “a specific embodiment” means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention and notnecessarily in all embodiments. Thus, respective appearances of thephrases “in one embodiment”, “in an embodiment”, or “in a specificembodiment” in various places throughout this specification are notnecessarily referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics of any specificembodiment of the present invention may be combined in any suitablemanner with one or more other embodiments. It is to be understood thatother variations and modifications of the embodiments of the presentinvention described and illustrated herein are possible in light of theteachings herein and are to be considered as part of the spirit andscope of the present invention.

It will also be appreciated that one or more of the elements depicted inthe drawings/figures can also be implemented in a more separated orintegrated manner, or even removed or rendered as inoperable in certaincases, as is useful in accordance with a particular application.

Additionally, any signal arrows in the drawings/Figures should beconsidered only as exemplary, and not limiting, unless otherwisespecifically noted. Combinations of components or steps will also beconsidered as being noted, where terminology is foreseen as renderingthe ability to separate or combine is unclear.

The foregoing description of illustrated embodiments of the presentinvention, including what is described in the Abstract, is not intendedto be exhaustive or to limit the invention to the precise formsdisclosed herein. While specific embodiments of, and examples for, theinvention are described herein for illustrative purposes only, variousequivalent modifications are possible within the spirit and scope of thepresent invention, as those skilled in the relevant art will recognizeand appreciate. As indicated, these modifications may be made to thepresent invention in light of the foregoing description of illustratedembodiments of the present invention and are to be included within thespirit and scope of the present invention.

Thus, while the present invention has been described herein withreference to particular embodiments thereof, a latitude of modification,various changes and substitutions are intended in the foregoingdisclosures, and it will be appreciated that in some instances somefeatures of embodiments of the invention will be employed without acorresponding use of other features without departing from the scope andspirit of the invention as set forth. Therefore, many modifications maybe made to adapt a particular situation or material to the essentialscope and spirit of the present invention. It is intended that theinvention not be limited to the particular terms used in followingclaims and/or to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include any and all embodiments and equivalents falling within thescope of the appended claims. Thus, the scope of the invention is to bedetermined solely by the appended claims.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. An extraction device for a prosthesis disposedin a bone having an exposed portion, comprising: a controller includinga trigger; a support having a proximal end and a distal end opposite ofsaid proximal end, said support further having a longitudinal axisextending from said proximal end to said distal end with said proximalend coupled to said controller, said support further having an adaptercoupled to said distal end with said adapter configured to engage theexposed portion of the prosthesis; and an oscillator coupled to saidcontroller and to said support, said oscillator configured to control aseries of vibratory pulses having an oscillation frequency and anoscillation magnitude of said support with said oscillation frequencyand said oscillation magnitude configured to extract the prosthesisresponsive to said series of vibratory pulses without impact forces; anda mechanical frame having a C-portion, said mechanical frame includingsaid adaptor wherein said C-portion includes a pair of lateral legscoupled to opposing ends of a longitudinal leg with said longitudinalleg generally parallel to an extraction axis of the prosthesis, whereinone of said lateral legs includes an inner surface including anextraction coupler mechanically communicated to said oscillator.
 2. Theextraction device of claim 1 wherein said series of vibratory pulsesincludes a vibratory motion having a frequency greater than or equal toabout 20 kHz.